Method for producing a perforated nacelle inlet assembly

ABSTRACT

A method for producing a nacelle inlet assembly includes forming a composite panel that has a carbon fiber reinforced polymer (CFRP) material. The composite panel is formed to have a curved contour that represents at least a portion of an annular barrel shape. The method includes applying a metallic coating to the composite panel to form a lipskin. The metallic coating is applied such that the metallic coating defines an exterior surface of the lipskin and the composite panel defines an interior surface of the lipskin. The method includes laser drilling a plurality of perforations through the lipskin. The laser drilling involves emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional conversion of, and claims priority to, U.S. Patent Application No. 63/368,560, filed Jul. 15, 2022, which is hereby incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure generally relate to the inlet section of a nacelle, such as an engine nacelle on an aircraft.

BACKGROUND

Some types of aircraft include propulsion systems attached to the wings, fuselage, or tail of the aircraft. The propulsion systems have nacelles which are outer casings for the propulsion equipment (e.g., engine). A nacelle includes an inlet section at a leading or front end of the nacelle. The nacelle may also include a fan cowl, a thrust reverser section, and an aft fairing section located behind the inlet section along a longitudinal length of the nacelle. The inlet section has an inner barrel that defines an air inlet duct for directing air to a fan and downstream propulsion equipment. The inner barrel may have an acoustic panel to facilitate noise reduction.

Ice on exterior surfaces of an aircraft is undesirable because the ice adds weight, can become dislodged in sheets that can damage rotors, leading edge surfaces of nacelles, and other aircraft components, and negatively affects the aerodynamics of the aircraft. To prohibit the formation of ice, some aircraft employ pneumatic anti-ice systems that convey a heated gas stream to warm components that are exposed to the exterior environment, such as wing leading edges and nacelle leading edges. For example, a heated air stream may be fan-driven to blow through a cavity along an interior surface of an engine inlet cowl, heating the inlet cowl from the inside. The heated components prevent ice accumulation along the exterior surfaces thereof.

The pneumatic, thermal anti-ice system has several drawbacks, though, including high power consumption, high complexity, and an undesirable impact on the aircraft propulsion system due to operational coupling. Regarding power consumption, the power demand to operate the anti-ice system can be substantial. For example, the thermal demand of an air heater and fans may be in the range of 2,000 to 11,000 Btu/hr-ft, which may be equivalent to a range of about 590 to about 3,200 W/ft. Regarding the high complexity, the pneumatic system has to control the heated air stream by integrating bulkheads into the engine inlet panels and wing leading edge panels and providing a network of conduits to convey the heated air. Regarding the complexity and the impact the propulsion system, some known pneumatic systems extract bleed air from a fuel combustion engine for the heated air stream. Utilizing engine bleed air may be complex due to various valves and conduits to control the bleed air. Furthermore, extracting the bleed air from the engine operationally couples the anti-ice system to the engine such that the operation of the anti-ice system may affect engine performance. Some of the engine settings may be directly impacted by the operation of the pneumatic anti-ice system. For example, depending on the engine operational setting, extracting bleed air to power the anti-ice system can stall the engine. In another example, during times that propulsion is not needed, such as a descent and/or slowing of the aircraft, the power demand of the anti-ice system may mandate that the engine continue generating thrust. Operating the engine to produce thrust when propulsion is not needed increases fuel consumption and reduces fuel efficiency.

SUMMARY OF THE DISCLOSURE

A need exists for a nacelle inlet assembly that incorporates an anti-ice system that avoids using a heated air stream as a working fluid, and that reduces the power demand (e.g., energy consumption) relative to the pneumatic anti-ice systems, providing better energy conservation and efficiency. More specifically, a need exists for producing a nacelle inlet assembly that includes perforations along a leading edge section of the inlet cowl to allow an anti-ice liquid to penetrate through the perforations onto an exterior surface of the inlet cowl. The anti-ice liquid may depress the freezing point along the exterior surface to prevent ice formation.

Certain embodiments of the present disclosure provide a method for producing a nacelle inlet assembly. The method includes forming a composite panel that includes a carbon fiber reinforced polymer (CFRP) material. The composite panel is formed to have a curved contour that represents at least a portion of an annular barrel shape. The method includes applying a metallic coating to the composite panel to form a lipskin. The metallic coating is applied such that the metallic coating defines an exterior surface of the lipskin and the composite panel defines an interior surface of the lipskin. The method includes laser drilling a plurality of perforations through the lipskin. The laser drilling involves emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface.

Certain embodiments of the present disclosure provide a perforation forming system that includes a laser device, a lipskin, and a control unit. The lipskin has a curved contour and includes an interior surface and an exterior surface. The lipskin includes a metallic coating that defines the exterior surface and a composite panel that defines the interior surface. The composite panel includes a carbon fiber reinforced polymer (CFRP) material. The control unit is operably connected to the laser device and is configured to control the laser device to laser drill a plurality of perforations through the lipskin. Each of the perforations is formed by the laser device emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface.

Certain embodiments of the present disclosure provide a method for producing a nacelle inlet assembly. The method includes forming a composite panel that includes a carbon fiber reinforced polymer (CFRP) material. The composite panel is formed to have a curved contour that represents at least a portion of an annular barrel shape. The method includes applying a metallic coating to the composite panel to form a lipskin. The metallic coating includes a nickel cobalt (NiCo) alloy. The metallic coating defines an exterior surface of the lipskin and the composite panel defines an interior surface of the lipskin. The method includes laser drilling a plurality of perforations through the lipskin. The laser drilling involves emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface. The perforations are laser drilled through the lipskin to have an average entry diameter at the interior surface of less than 100 microns and an average exit diameter at the exterior surface of less than 60 microns.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like numerals represent like parts throughout the drawings, wherein:

FIG. 1 is a perspective illustration of an aircraft.

FIG. 2 illustrates an embodiment of a nacelle of a propulsion system of an aircraft according to an embodiment.

FIG. 3 is a front view of an inlet cowl of the nacelle shown in FIG. 2 .

FIG. 4 is a perspective view of the inlet cowl shown in FIGS. 2 and 3 , showing an aft edge thereof.

FIG. 5 is a cross-sectional view of a portion of an inlet assembly according to an embodiment.

FIG. 6 illustrates an enlarged, schematic rendering of the inlet assembly at a leading edge according to an embodiment.

FIG. 7 is a cross-sectional view of a nose portion of the inlet assembly according to an embodiment.

FIG. 8 is an enlarged view of a segment of the nose portion shown in FIG. 7 .

FIG. 9 is a perspective cross-sectional view of a portion of the inlet assembly according to an embodiment.

FIG. 10 is a schematic diagram depicting a process of assembling an inlet assembly according to an embodiment.

FIG. 11 is a block diagram of a second aircraft according to an embodiment.

FIG. 12 is a side cross-sectional view of a portion of the inlet assembly according to an embodiment.

FIG. 13 illustrates a laser device and a cross-sectional view of a section of the lipskin during a laser drilling process according to an embodiment.

FIG. 14 illustrates a perforation forming system according to an embodiment.

FIG. 15 is a flow chart of a method for producing a perforated inlet assembly of a nacelle according to an embodiment.

DETAILED DESCRIPTION OF THE DISCLOSURE

The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the appended drawings. As used herein, an element or step recited in the singular and preceded by the word “a” or “an” should be understood as not necessarily excluding the plural of the elements or steps. Further, references to “one embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional elements not having that property.

This invention was made with UK Government support under 22482-UK Aerospace Research and Technology Programme. The UK Government may have certain rights in this invention.

Certain embodiments of the present disclosure provide a method for producing a perforated nacelle inlet assembly. The inlet assembly has perforations along a leading edge section of an inlet cowl to allow an anti-ice liquid of a fluid ice protection system (FIPS) to weep through the perforations onto the exterior surface of the inlet cowl. The perforations are laser drilled through a lipskin of the inlet cowl. The lipskin, according to the embodiments described herein, is a stack including at least a composite panel and a metallic coating. The metallic coating defines the exterior surface of the lipskin (and the inlet cowl) that is exposed to environment elements, such as sunlight, moisture, debris, wind, birds, and the like. The composite panel defines an interior surface of the lipskin (and the inlet cowl). The composite panel may include a carbon fiber reinforced polymer (CFRP) material. The perforations are laser drilled through the entire thickness of the lipskin, penetrating both the composite panel and the metallic coating. In an embodiment, the perforations are micron-sized holes which enable the transfer of the anti-ice liquid therethrough via capillary action.

The embodiments described herein provide a method to conduct laser micro-perforation through the metallic and CFRP material lipskin stack using a fiber laser. The fiber laser is controlled to generate a series of micron-scale holes with consistent hole properties and good hole quality (imparting negligible, if any, damage to surrounding material). Generating micron-scale holes is preferable to avoid adversely affecting aerodynamic flow along the exterior surface of the inlet cowl. Forming such small holes in a composite lipskin is difficult and has various issues, even when using focused laser ablation. For example, the resin and fibers within the CFRP material may have widely differing optical and thermal resistance properties, such that the laser beam may cause considerable damage to the CFRP material surrounding the perforations. The resin may chip, and the fibers may get damaged and displaced. The ablation through the CFRP material may cause the perforations to be elongated or oblong, rather than circular, in shape due to a non-isotropic nature of the fiber bundles that results in elliptical resin burn-out. Another issue is determining a proper focus position of the laser to penetrate the multiple layers of the lipskin because the CFRP composite panel may have a relatively substantial thickness, such as at least 2 or 3 mm. Another concern is weakness or loss of rigidity that may occur along the lipskin as a result of the laser drilling process to form the perforations. If the perforation size and pitch (e.g., spacing) between perforations is too narrow, the lipskin may be structurally degraded. Furthermore, laser drilling of the lipskin may eject gaseous byproducts into the ambient air surrounding the laser and the lipskin. The gaseous byproducts may need to be extracted from the ambient air to meet desired air quality properties.

The inlet assembly described herein may be designed to enhance laminar fluid flow along an exterior surface of the inlet cowl. Enhancing laminar flow along the outer side of the inlet cowl may result in improved aerodynamic performance, such as greater fuel efficiency, relative to conventional inlet cowls. The laminar fluid flow may be enhanced by extending a longitudinal length of a laminar flow region along the exterior surface of the inlet cowl. The laminar flow region may be elongated by designing the outer side of the inlet cowl to have a contour that promotes laminar fluid flow and is seamless along the exterior surface. For example, an outer side of the inlet cowl may be seamless from a leading edge of the inlet cowl to an outer aft edge of the outer side. The exterior surface of the outer side may be relatively smooth and uniform along the length, providing a surface quality that promotes laminar flow. The exterior surface may be defined by a metallic coating of a lipskin of the inlet cowl. The metallic coating may define the leading edge and the entire length of the exterior surface of the outer side from the leading edge to the outer aft edge. The inlet assembly described herein may have a continuous material system in which the metallic coating of the lipskin seamlessly extends along the leading edge of the inlet cowl and the entire length of the outer side of the inlet cowl. Conventional inlet cowls may include seams at interfaces between the lipskin and the outer barrel panel. The seams cause turbulent fluid flow along the exterior surface, which is detrimental to flight and engine performance.

In an embodiment, the laminar flow region may be elongated by extending the length of the outer side of the inlet cowl. For example, the inlet cowl may include an extended section that longitudinally projects, in an aft direction, beyond an inner aft edge of an inner side of the inlet cowl. The extended section may be located aft of a fan cowl interface and/or A flange. The laminar flow region may extend along at least a portion of the extended section, promoting laminar flow along the inlet cowl beyond the traditional fan cowl split line. The extended section may be structurally supported by a rigid and strong carbon fiber reinforced polymer (CFRP) material of a composite panel of the lipskin, along which the metallic coating is disposed. Optionally, the extended section may be structurally supported by support frames that extend from the inner side of the inlet cowl to the extended section of the outer side. The support frames and/or CFRP material provide rigidity to maintain the designed contour of the outer side of the inlet cowl to extend the laminar flow region onto the extended section.

The inlet assembly described herein may be incorporated with a fluid ice protection system (FIPS) that is designed to prohibit ice formation on and/or remove accumulated ice from the leading edge section of the inlet cowl. The inlet assembly with the perforated leading edge of the inlet cowl, as described herein, is designed to be incorporated with a hydraulic (liquid) FIPS. The FIPS may supply an anti-ice liquid into the inlet cowl, for the liquid to weep through the perforations onto the exterior surface of the lipskin, defined by the metallic coating. The liquid prevents the formation of ice (and removes any ice already present) along the inlet, which can be detrimental to flight and engine performance. The FIPS may include a plenum back wall that is coupled to the interior surface of the lipskin to define a plenum (e.g., cavity). The anti-ice liquid is supplied to the plenum through one or more conduits that extend from a reservoir remote from the inlet cowl. The FIPS may include one or more membranes within the plenum that absorb and distribute the anti-ice liquid to the perforations. For example, the membrane(s) may extend across and cover all or a majority of the perforations, such that the anti-ice fluid enters the perforations from the membrane(s).

Referring now to the drawings, which illustrate various embodiments of the present disclosure, FIG. 1 is a perspective illustration of an aircraft 100. The aircraft 100 may include a fuselage 102 extending from a nose 103 to an empennage 104. The empennage 104 may include one or more tail surfaces for directional control of the aircraft 100. The aircraft 100 includes a pair of wings 106 extending from the fuselage 102. One or more propulsion systems 108 propel the aircraft 100. The propulsion systems 108 are supported by the wings 106 of the aircraft 100, but may be mounted to the fuselage or tail in other types of aircraft. Each propulsion system 108 includes a rotor assembly 119 with rotors that spin to direct air.

The rotor assembly 119 of each propulsion system 108 is surrounded by a nacelle 110. The nacelle 110 is an outer casing or housing that holds the rotor assembly 119. The nacelle 110 includes an inlet section, referred to as an inlet cowl, at a leading or front end of the nacelle 110. The nacelle 110 may also include a fan cowl, a thrust reverser section, and an aft fairing section located behind the inlet cowl along a longitudinal length of the nacelle 110. The inlet cowl has an inner barrel that defines an air inlet duct for directing air to the rotor assembly 119. The inner barrel may have an acoustic panel to facilitate reducing noise created by the rotor assembly 119. The nacelle 110 may have an exhaust nozzle 112 (e.g., a primary exhaust nozzle and a fan nozzle) at an aft end of the propulsion system 108.

In an embodiment, each propulsion system 108 may include or represent a gas turbine engine. The rotor assembly 119 may be a portion of the engine. The engine burns a fuel, such as gasoline or kerosene, to generate thrust for propelling the aircraft 100.

In an alternative embodiment, the rotor assemblies 119 of some of all of the propulsion systems 108 may be driven by electrically-powered motors, rather than by the combustion of fuel within a gas turbine engine. For example, the motors of such propulsion systems 108 may be electrically-powered by an onboard electrical energy storage device (e.g., a battery system) and/or an onboard electrical energy generation system.

FIG. 11 is a block diagram of a second aircraft 150 according to an embodiment. The aircraft 150 in FIG. 11 may be an all-electric aircraft that lacks any fuel combustion engine, or a hybrid aircraft that includes at least one fuel combustion engine. The aircraft 150 includes an electrical energy storage device (EESD) 152, a fluid ice protection system (FIPS) 154, and a propulsion system 156. The propulsion system 156 includes a nacelle 158 that surrounds a motor 160 and a rotor assembly 162 (“rotors” in FIG. 11 ). The motor 160 is powered by electric current supplied from the EESD 152. The EESD 152 may be a battery system that includes at least one battery cell. Optionally, the EESD 152 may include one or more capacitors or other charge-storing devices. The EESD 152 may be rechargeable.

The aircraft 150 includes a controller 164 that has one or more processors. The controller 164 may control the delivery of electric current to the motor 160 via one or more switch devices (SD) 166 along a power delivery circuit path between the EESD 152 and the motor 160. The motor converts electrical energy to mechanical energy that exerts a torque on the rotor assembly 162 to spin the rotors. The aircraft 150 may be an unmanned aerial vehicle (e.g., a drone), a passenger aircraft, or the like.

The FIPS 154 supplies an anti-ice liquid to an inlet cowl 168 of the nacelle 158 to prohibit the formation of ice along a leading edge 170 of the nacelle 158. The anti-ice liquid is conveyed through one or more conduits 172 that form a fluid delivery network. The FIPS 154 may be powered by electric current supplied from the EESD 152 or another onboard electrical energy storage device. The operation of the FIPS 154 may be controlled by the controller 164, or another controller. All of the components shown in FIG. 11 may be disposed onboard the aircraft 150. The aircraft 150 may include more than one of the illustrated components, such as multiple propulsion systems 156.

FIG. 2 illustrates an embodiment of a nacelle 200 of a propulsion system of an aircraft according to an embodiment. The nacelle 200 may be one of the nacelles 110 of the propulsion systems 108 shown in FIG. 1 and/or the nacelle 158 of the propulsion system 156 shown in FIG. 11 . The nacelle 200 extends a length from a front end 202 of the nacelle 200 to an aft end 204 of the nacelle 200 (opposite the front end 202). The nacelle 200 may include an inlet cowl 206 and a fan cowl 208. The inlet cowl 206 defines a leading edge 210 of the nacelle 200 at the front end 202, to direct air into a core 212 of the nacelle 200. The fan cowl 208 is aft of the inlet cowl 206 and is connected to the inlet cowl 206. The fan cowl 208 may connect to and extend from an outer aft edge 214 of the inlet cowl 206. The fan cowl 208 may surround the rotor assembly, such as one or more fans mounted at a forward end of an engine within the core 212.

The nacelle 200 may include a mount 216 for securing the nacelle 200 and the rotary components held by the nacelle 200 to the aircraft. The mount 216 may be a pylon. The nacelle 200 includes at least one aft section 218 that is disposed aft of the fan cowl 208 along the length of the nacelle 200. When the nacelle 200 holds a gas turbine engine, the aft section(s) 218 may surround engine components such as a compressor, combustion chamber (or combustor), and turbine. The aft section(s) 218 may include or represent a thrust reverser, aft fairing, or the like. The aft section(s) 218 may define the aft end 204 and an aft nozzle through which air and exhaust products are emitted from the propulsion system.

FIG. 3 is a front view of the inlet cowl 206 shown in FIG. 2 . FIG. 4 is a perspective view of the inlet cowl 206 shown in FIGS. 2 and 3 , showing the outer aft edge 214 of the inlet cowl 206. The inlet cowl 206 has an annular barrel shape that defines a central opening 230. The term “annular barrel shape” means that the inlet cowl 206 defines a closed, ring-like shape when viewed from the front. The annular barrel shape is oriented about a central longitudinal axis 207. The central longitudinal axis 207 extends through the central opening 230. The inlet cowl 206 may have a generally cylindrical shape. For example, the leading edge 210 may be circular. The inlet cowl 206 directs air through the central opening 230 into the core 212 of the nacelle 200 shown in FIG. 2 .

The inlet cowl 206 has the leading edge 210, an outer side 232 and an inner side 234. The outer side 232 extends from the leading edge 210 to the outer aft edge 214. The inner side 234 extends from the leading edge 210 to an inner aft edge 235 of the inner side 234. The outer side 232 is radially outside of the inner side 234 and surrounds the inner side 234. The outer side 232 and inner side 234 optionally may be referred to as an outer barrel portion and an inner barrel portion, respectively. The inner side 234 may define the central opening 230, and operates as an intake duct to supply air into the core 212 for the rotor assembly 119. The inlet cowl 206 defines a cavity 242 that is aft of the leading edge 210 and radially disposed between the outer side 232 and the inner side 234. The cavity 242 is closed at a front end 244 of the inlet cowl 206, and open at a rear or aft end 246 of the inlet cowl 206.

The inlet cowl 206 may include a lipskin 236 and an acoustic panel 238. In an embodiment, the lipskin 236 defines the leading edge 210 and the outer side 232. The acoustic panel 238 is coupled to the lipskin 236 along the inner side 234, and the acoustic panel 238 defines a length of the inner side 234. For example, the lipskin 236 may define a front portion of the inner side 234, and the acoustic panel 238 may define a rear or aft portion of the inner side 234. The acoustic panel 238 is located forward of the fan cowl 208. The acoustic panel 238 may be located in relatively close proximity to one or more fans or other rotary equipment. The acoustic panel 238 may have a plurality of acoustic perforations for absorbing noise generated by the rotor assembly and/or the airflow passing through the inlet cowl 206.

FIG. 4 shows an inlet assembly 240 that includes the inlet cowl 206 and one or more support frames 250. The inlet assembly 240 includes multiple support frames 250 in the illustrated embodiment. The support frames 250 are disposed within the cavity 242 of the inlet cowl 206 to mechanically support the contour of the inlet cowl 206. For example, the support frames 250 extend across the cavity 242 from the inner side 234 to the outer side 232 to provide structural rigidity to the inlet cowl 206 (e.g., the lipskin 236 and the acoustic panel 238). The support frames 250 may help withstand pressure and other forces exerted on the exterior surface 248 without deflecting and changing the contour of the outer side 232. For example, deflection of the outer side 232 changes the contour, which may disrupt the laminar fluid flow along the exterior surface 248. One or more of the support frames 250 may be open truss-like structures that enable air flow through openings in the support frames 250 (within the cavity 242). In an embodiment, the inlet assembly 240 may lack bulkheads that partition the cavity 242 into multiple channels or regions that are blocked off from each other (e.g., fluidly isolated from each other). Avoiding bulkheads which sub-divide the cavity 242 may reduce the complexity of manufacturing the inlet assembly 240 relative to conventional inlets.

The inlet assembly 240 may also include one or more components of a fluid ice protection system (FIPS) 262 (shown in FIG. 6 ) integrated into the cavity 242 of the inlet cowl 206. The FIPS 262 supplies an anti-ice liquid onto the exterior surface 248 of the inlet cowl 206 to prohibit ice formation on the exterior surface 248. The exterior surface 248 that receives the anti-ice liquid is a leading edge section 258 (shown in FIG. 5 ) of the inlet cowl 206 that encompasses the leading edge 210. The exterior surface 248 is exposed to the elements, such as sunlight, moisture, debris, wind, birds, etc.

FIG. 5 is a cross-sectional view of a portion of the inlet assembly 240 according to an embodiment. The illustrated portion shows the lipskin 236 of the inlet cowl 206 without the acoustic panel 238. For example, the acoustic panel 238 may couple to an inner edge 254 of the lipskin 236 during the assembly process. The lipskin 236 in the illustrated embodiment has a curved shape that radially and longitudinally extends forward from the inner edge 254 to the leading edge 210, and then rearward to an outer, aft edge 256 of the lipskin 236. The lipskin 236 may be relatively thin. The area of the inlet cowl 206 (e.g., the lipskin 236 thereof) that includes the leading edge 210 and the areas radially adjacent the leading edge 210 is referred to herein as a front or leading edge section 258 of the lipskin 236. The outer, aft edge 256 may define the aft edge 214 of the inlet cowl 206, such that the lipskin 236 extends the full length of the inlet cowl 206 along the outer side 232.

In an embodiment, the exterior surface 248 of the inlet cowl 206 is smooth and defined by a single, continuous construct along the entire length of the outer side 232. For example, a metallic coating 272 (shown in FIG. 6 ) of the lipskin 236 may define the exterior surface 248 along the entire length of the outer side 232 from the leading edge 210 to the outer aft edge 214 of the inlet cowl 206. There are no seams, joints, or interfaces along the outer side 232, which promotes laminar air flow along the aerodynamic exterior surface 248 by avoiding turbulence-inducing interfaces. The inlet assembly 240 may provide a longer and/or larger surface area along which the air flow is laminar, than conventional inlets, as described in more detail with reference to FIGS. 9 and 12 . The enlarged laminar flow region may provide a substantial drag benefit and fuel efficiency gain over conventional inlets.

The components of the FIPS 262 integrated into the inlet assembly 240 may include a plenum back wall 260 that is affixed to the inlet cowl 206. The plenum back wall 260 is disposed within the cavity 242 of the inlet cowl 206 and extends along the leading edge section 258 of the inlet cowl 236. The plenum back wall 260 may be affixed to an interior surface 264 of the inlet cowl 206. In an embodiment, the plenum back wall 260 is bonded to the interior surface 264. In an embodiment, the lipskin 236 of the inlet cowl 206 includes two (e.g., first and second) integrated protrusions 266 along the interior surface 264 that serve as mounts on which to affix the plenum back wall 260. The protrusions 266 project from the interior surface 264 into the cavity 242. The protrusions 266 may be integral to the lipskin 236. In an alternative embodiment, the protrusions 266 may be discrete components that are themselves mounted to the interior surface 264 and serve to indirectly secure the plenum back wall 260 to the lipskin 236. The plenum back wall 260 is mounted to the inlet cowl 206 to define a plenum 267 (e.g., fluid manifold) for receiving and containing the anti-ice liquid of the FIPS 262. The plenum 267 is longitudinally defined between the interior surface 264 of the lipskin 236 and a front surface 268 of the back wall 260. The plenum 267 is radially defined between the two protrusions 266. The plenum 267 may be located along the leading edge section 258 of the lipskin 236 only. For example, the plenum 267 may not extend along the outer side 232.

FIG. 6 illustrates an enlarged, schematic rendering of the inlet assembly 240 at the leading edge 210 according to an embodiment. The illustrated components in FIG. 6 are depicted for ease of description, and may not be drawn to scale. The lipskin 236 of the inlet cowl 206 in an embodiment is a stack-up of multiple different layers. The lipskin 236 may include at least a composite panel 270 and a metallic coating 272. The metallic coating 272 is exterior of the composite panel 270 to provide an erosion shield that protects the composite panel 270 from leading edge damage. The metallic coating 272 may define the exterior surface 248 of the inlet cowl 206 along at least the leading edge section 258, and optionally all of the surface area of the inlet cowl 206 that is exposed to the environmental elements. The composite panel 270 and metallic coating 272 may continuously extend the full length of the lipskin 236.

The composite panel 270 has an interior surface 274 and an exterior surface 276 opposite the interior surface 274. The interior surface 274 may define the interior surface 264 of the inlet cowl 206. The metallic coating 272 is disposed along the exterior surface 276 of the composite panel 270. In an embodiment, the metallic coating 272 is indirectly connected to the exterior surface 276 via one or more intervening layers. The one or more intervening layers may include an electrically conductive layer 278 that is provided to assist with the application of the metallic coating 272 on the composite panel 270. The conductive layer 278 may be a metallic material that has a different composition than the metallic coating 272. For example, the conductive layer 278 may be a thin silver (Ag) loaded sheet.

In an embodiment, the composite panel 270 is or includes carbon fiber. For example, the composite panel 270 may have a carbon fiber reinforced polymer (CFRP) material. The polymer may be a plastic (e.g., thermoplastic) or the like. The metallic coating 272 may be a metal alloy. For example, the metallic coating 272 in an embodiment is a nickel-cobalt (NiCo) alloy. The metallic coating 272 may be deposited onto the lipskin 236 to solidify and harden. In an embodiment, the metallic coating 272 is applied via electroplating. For example, the metallic coating 272 may be a NiCo alloy that is electroplated directly onto the conductive layer 278 of the lipskin 236.

The lipskin 236 of the inlet cowl 206 may define multiple perforations 280 that penetrate the thickness of the lipskin 236 along the leading edge section 258. The perforations 280 may extend continuously through the composite panel 270, the conductive layer 278, and the metallic coating 272. The perforations 280 are aligned with and open to the plenum 267, such that the perforations 280 are fluidly connected to the plenum 267 and receive anti-ice liquid 282 from the plenum 267. The characteristics of the perforations 280, such as diameter, location, percent-open-area, etc., may be selected based on application-specific parameters. In an embodiment, the perforations 280 have micron scale diameters. For example, a diameter of each perforation may be less than 100 microns. The microscopic perforations 280 may be formed via laser drilling. The tiny perforations 280 enable to the liquid 282 under pressure to slowly weep through the perforations 280 onto the exterior surface 248. The anti-ice liquid 282 may be a solution that provides freezing point depression. For example, the anti-ice liquid 282 may be a propylene glycol-based solution, an ethylene glycol-based solution, or the like.

The components of the FIPS 262 that are illustrated in FIG. 6 include the plenum back wall 260, a fluid delivery conduit 284 that is coupled to the plenum back wall 260, and one or more membranes 286. The conduit 284 may be a duct, tube, or the like that is a component of a fluid delivery network of the FIPS 262. The fluid delivery network provides a path from a fluid reservoir to the plenum 267. The anti-ice liquid 282 may be pumped through the conduit 284 into the plenum 267 through an aperture in the back wall 260. The one or more membranes 286 are disposed within the plenum 267 (e.g., between the lipskin 236 and the back wall 260) and receive the anti-ice liquid 282. A single membrane 286 is shown in FIG. 6 . The membrane 286 may be designed to absorb and distribute the anti-ice liquid 282 to the perforations 280. The membrane 286 may be secured to the interior surface 264 of the inlet cowl 206, such as by bonding. The membrane 286 aligns with the perforations such that the membrane 286 may extend across and cover all or a majority of the perforations 280. The membrane 286 may spread the anti-ice liquid 282 along a length of the membrane 286 which supports a more uniform distribution of the liquid 282 among the perforations 280. The membrane 286 optionally may be a porous material, such as a porous plastic material, an open-celled foam material, or the like.

In an embodiment, the plenum back wall 260 includes first and second flanges 288 at respective ends of the back wall 260. The flanges 288 are secured to the protrusions 266 of the lipskin 236 along respective contact interfaces 290. The flanges 288 may be bonded to the protrusions 266 at the contact interfaces 290. The bonding may be accomplished via application of an adhesive, a heat treatment, and/or the like. In an embodiment, the contact interfaces 290 are angled transverse to the tangent of the interior surface 264 of the lipskin 236 proximate to the contact interfaces 290 to enhance retention of the plenum back wall 260 to the lipskin 236. The contact interfaces 290 extend along ramp surfaces 296 of the protrusions 266. The contact interfaces 290 have vectors 292 that are not parallel to the tangent 294 of the interior surface 262. The contact interfaces 290 are angled to shift the pressure loading dynamics along the bonded interfaces 290 and enable the plenum back wall 260 to withstand more force before separating from the lipskin 236, relative to bonding the back wall 260 to a flat or non-projecting area of the interior surface 264 of the lipskin 236.

For example, the plenum 267 may experience pressure that tends to force the plenum back wall 260 away from the leading edge 210, as indicated by the force arrows 298. Furthermore, the composite panel 270 and the protrusions 266 are not metallic, so the plenum back wall 260 cannot be welded to the lipskin 236. In an embodiment, the protrusions 266 may be composed of a rigid, closed-cell foam. By bonding the flanges 288 to the protrusions 266 along the angled contact interfaces 290, the forces exerted on the back wall 260 are withstood by shear retention along the contact interfaces 290. For example, the forces on the back wall 260 may be acutely angled relative to the interface vectors 292, which is resisted in part by shear loading at the interfaces 290. Without the angled contact interfaces 290, the forces on the back wall 260 may peel the back wall 260 off the interior surface 264 of the lipskin 236, obstructing, if not entirely foiling, operation of the FIPS 262.

FIG. 7 is a cross-sectional view of a nose portion of the inlet assembly 240 according to an embodiment. FIG. 8 is an enlarged view of a segment of the nose portion shown in FIG. 7 . The views in FIGS. 7 and 8 may be more accurate in terms of scale and shapes of the components relative to the illustration in FIG. 6 . FIG. 7 shows the leading edge 210 of the lipskin 236, the plenum back wall 260, the protrusions 266, and the membrane 286. With reference to both FIGS. 7 and 8 , the thin membrane 286 is disposed within the plenum 267. The flanges 288 of the back wall 260 are secured to the ramp surfaces 296 of the protrusions 266, as described with reference to FIG. 6 . In an embodiment, the plenum back wall 260 may be a composite structure. For example, the back wall 260 may include a core layer 302 sandwiched between two outer layers 304. The core layer 302 may be a honeycomb structure. In an embodiment, the protrusions 266 may include a rigid, closed-cell foam material. The protrusions 266 may be integrated onto the lipskin 236, such as formed as portions of the CFRP composite panel 270.

FIG. 9 is a perspective cross-sectional view of a portion of the inlet assembly 240 according to an embodiment. The acoustic panel 238 longitudinally extends along the inner side 234, and the lipskin 236 longitudinally extends the length of the outer side 232. The plenum back wall 260 is disposed at the front end of the cavity 242, interior of the leading edge 210. The inlet assembly 240 may include support frames 250 within the cavity 242 to mechanically support the extended length of the lipskin 236 and withstand forces exerted on the lipskin 236 to maintain the shape of the inlet cowl 206.

In an embodiment, the support frames 250 include longitudinally-extending support frames 322 that are circumferentially spaced apart. The support frames 250 may also include circumferentially-extending support frames 324. The circumferentially-extending support frames 324 may be located proximate to the outer aft edge 214 of the inlet cowl 206. For example, the support frames 324 may be coupled to a flange 326 mounted to an aft edge 328 of the acoustic panel 238, which defines the inner aft edge 235 of the inlet cowl 206. The support frames 324 may be perpendicular to the support frames 322. The support frames 322, 324 may all radially extend across the cavity 242 from the outer side 232 to the inner side 234, and may be coupled to both the outer and inner sides 232, 234. In an embodiment, the support frames 322, 324 are open, truss-like structures that permit fluid flow through openings 330 in the frames 322, 324. The support frames 322, 324 may be rearward or aft of the plenum back wall 260.

In an embodiment, the outer side 232 extends rearward beyond the inner aft edge 235 of the inner side 234. The portion of the outer side 232 that extends beyond the inner aft edge 235 is an extended section 334 of the outer side 232. The extended section 334 may overhang relative to the acoustic panel 238. The inlet assembly 240 may include one or more angled support frames 332 to support the overhanging, extended section 334 of the outer side 232.

FIG. 12 is a side cross-sectional view of a portion of the inlet assembly 240 according to an embodiment. The inlet assembly 240 may be the same as the inlet assembly 240 shown in FIG. 9 , except that the plenum back wall 260 and the longitudinally-extending and circumferentially-extending support frames 322, 324 are omitted from FIG. 12 . In an embodiment, the exterior surface 248 of the inlet cowl 206 is seamless along an entire length of the outer side 232 from the leading edge 210 to the outer aft edge 214.

The lipskin 236 may define both the leading edge section 258 (including the leading edge 210) and the outer side 232. For example, both the composite panel 270 and the metallic coating 272 of the lipskin 236 extend the entire length of the outer side 232 from the leading edge 210 to the outer aft edge 214. The metallic coating 272 may define the exterior surface 248 of the inlet cowl 206 along an entirety of both the leading edge section 258 and the outer side 232. The metallic coating 272 provides an erosion shield for the composite panel 270, and also provides a relatively smooth, uniform surface that promotes laminar flow. Because the metallic coating 272 continuously extends from the leading edge 210 to the outer aft edge 214, the outer side 232 is free of seams, joints, and other types of material interfaces. The lipskin 236 couples to the acoustic panel 238 at a joint 340. The joint 340 is disposed along the inner side 234 of the inlet cowl 205. The flow characteristics of air along the inner side 234 may not have as significant of an effect on flight performance and fuel efficiency as the flow characteristics along the outer side 232. As shown in FIG. 12 , the acoustic panel 238 may be substantially thicker than a thickness of the lipskin 236.

In an embodiment, the inlet cowl 206 is designed to achieve a relatively long laminar flow region along the exterior surface 248 of the outer side 232. The laminar flow region is an area along which the moving air flow (during flight of the aircraft) is characterized by laminar flow, rather than turbulent flow. For example, a contour of the outer surface 232 may be designed to promote laminar flow. The contour may be designed based on laminar flow theory. Furthermore, the exterior surface 248 of the outer side 232 is defined by a smooth metallic coating 272 and is devoid of seams and other discontinuities. The laminar flow region may extend along the contour of the outer side 232 for the entire length of the outer side 232 (e.g., from the leading edge 210 to the outer aft edge 214).

FIG. 12 shows the extended section 334 of the outer side 232 of the inlet cowl 206 that longitudinally projects beyond the inner aft edge 235 of the inner side 234. The extended section 334 extends to, and includes, the outer aft edge 214. The extended section 334 may be a seamless extension of the contour of the outer side 232. For example, the lipskin 236 may define the extended section 334, and the metallic coating 272 may define the exterior surface 248 of the inlet cowl 206 along the extended section 334. The laminar flow region may extend along the contour of the outer side 232 onto the extended section 334. By providing the extended section 334, the length of the laminar flow region may be elongated relative to not including the extending section 334. For example, the laminar flow region may longitudinally extend beyond a location at which the inner side 234 of the inlet cowl 206 interfaces with the fan cowl 208. The location at which the inner side 234 interfaces with the fan cowl 208 may be the flange 326 (e.g., the A flange), a fan cowl split line, and/or the like.

In an embodiment, the extended section 334 may be structurally supported by one or more angled support frames 332 within the cavity 242. For example, the angled support frame 332 may be assembled to maintain the contour of the outer side 232 along the extended section 334. The angled support frame 332 may prohibit the extended section 334 from deflecting from applied forces during operation, which could disrupt the laminar flow along the extended section 334. The angled support frame 332 has a first end 342 that contacts the extended section 334 and a second end 344 that contacts the inner side 234. For example, the second end 344 may be coupled to the flange 326 and/or to the acoustic panel 238. In an embodiment, the angled support frame 332 is triangular and defines one or more openings 346 through the support frame 332. For example, the angled support frame 332 includes a first leg 348 that radially extends across the cavity from the first end 342 to the second end 344. The support frame 332 includes a second leg 350 that longitudinally extends along a length of the extended section 334 and engages the extended section 334. The support frame 332 includes a third, angled leg 352 that extends across the cavity 342 from the inner side 234 to the extended section 334 and defines a hypotenuse of the triangular shape. In an alternative embodiment, the angled support frame 332 may not be triangular. For example, the support frame 332 may only include the first and second legs 348, 350 (not the third leg 352), or may only include the third leg 352 (not the first and second legs 348, 350). In another alternative embodiment, the angled support frame 332 may be an integral portion of the longitudinally-extended support frame 322 shown in FIG. 9 , rather than a discrete component.

In an alternative embodiment, the extended section 334 may be inherently structurally supported by the composite panel 270 of the lipskin 236, instead of by the angled support frame(s) 332. For example, the composite panel 270 may include CFRP material that extends along the full length of the extended section 334 and has sufficient strength to structurally maintain the contour of the outer side 232, without discrete support frames. Optionally, the lipskin 236 may be formed such that additional plies of CFRP material are stacked along the extended section 334. As a result, the composite panel 270 may be thicker along the extended section 334 than along other portions of the lipskin 236, such as the leading edge section 258. FIG. 12 shows a thicker section 360 of the composite panel 270 along the extended section 334. Although FIG. 12 shows both the angled support frame 332 and the thicker section 360 of the composite panel 270, these features may be alternatives. For example, the angled support frame 332 may be installed without thickening the CFRP composite panel 270, or the CFRP composite panel 270 may be thickened to avoid installation of the angled support frame 332.

FIG. 10 is a schematic diagram depicting a process of producing an inlet assembly according to an embodiment. The inlet assembly manufactured by the process may be the inlet assembly 240 shown in FIGS. 4 through 9 . At box 400, a curved tool 310 is prepped for a layup process. The curved tool 310 may be a mold or mandrel. The tool 310 may have a shape that corresponds to a desired shape of the inlet cowl. At box 402, a carbon fiber reinforced polymer (CFRP) material is applied on the curved tool 310 to form the composite panel 270 via a layup process. The layup process may be an automated fiber placement (AFP) process in which multiple plies or layers of fiber-reinforced material are applied on the tool 310. The plies may include tows or bundles of carbon fibers impregnated with an epoxy resin. The tows may be applied in different orientations relative to one another. Although not shown, the protrusions 266 of the lipskin 236 may be formed during the layup step shown in box 402.

The composite panel 270 may then be cured via a heat treatment and removed from the tool 310. Optionally, the conductive layer 278 may be applied to the exterior surface 276 of the composite panel 270. At box 408, non-plated areas of the composite panel 270 are masked by a maskant 312. The conductive layer 278, if present, may be co-cured at box 410.

At box 412, the metallic coating 272 is applied on the composite panel 270 (and conductive layer 278) by electroplating. The metallic coating 272 is shown in the inset enlarged view in box 414. The metallic coating 272 may be a nickel alloy, such as NiCo. At box 416, the maskant is removed from the structure, yielding the lipskin 236 (or stack). At box 418, the lipskin 236 is laser drilled to form perforations 280 through the thickness thereof in the leading edge section 258. At box 420, the membrane 286 is applied along the interior surface 264 of the inlet cowl 206 (e.g., the lipskin 236) to cover the perforations 280.

Box 422 shows a portion of the completed inlet assembly 240, similar to the view in FIG. 7 . The assembly process may include additional steps not depicted in FIG. 10 , such as bonding the plenum back wall 260 to the composite panel 270 and connecting the fluid delivery conduit 284 to the plenum back wall 260. Additional portions of the FIPS 262 may need to be assembled before the FIPS 262 is operational.

FIG. 13 illustrates a laser device 500 and a cross-sectional view of a section 502 of the lipskin 236 during a laser drilling process according to an embodiment. As described above with reference to FIGS. 6 and 10 , the laser device 500 is controlled to laser drill a plurality of the perforations 280 through a thickness of the lipskin 236 along the leading edge section 258 of the lipskin 236. In an embodiment, the perforations 280 are formed by laser drilling in an inside-out configuration after the section 502 of the lipskin 236 is formed. For example, the section 502 of the lipskin 236 includes at least the composite panel 270 and the metallic coating 272, optionally with the conductive layer 278 (shown in FIG. 6 ) disposed therebetween. The composite panel 270 is, or includes, a CFRP material. The composite panel 270 defines the interior surface 264 of the lipskin 236. The metallic coating 272 defines the exterior surface 248 of the lipskin 236, opposite the interior surface 264.

In the inside-out configuration, the laser device 500 emits a laser beam 504 that impinges upon the interior surface 264 of the lipskin 236 and penetrates the CFRP material of the composite panel 270. Upon passing through the CFRP material, the laser beam 504 penetrates the metallic coating 272 and exits the lipskin 236 through the exterior surface 248. The laser beam 504 penetrates the thickness of the lipskin 236 in the direction from the inside (or interior) towards the outside (or exterior). The laser device 500 may be systematically and automatically controlled by a controller or control unit to emit the laser beam 504 at different locations along the section 500 over time to form the plurality of perforations 280.

The laser device 500 is designed and controlled to form perforations 280 in the lipskin 236 that have micron scale diameters. Each perforation 280 has an entry 506 along the interior surface 264 and an exit 508 along the exterior surface 248. In an embodiment, the average exit diameter 510 at the exits 508 is less than 100 microns (micrometers). For example, the average exit diameter 510 may be less than 80 microns, or even less than 60 microns. In an embodiment, the average entry diameter 512 at the entries 506 is less than 400 microns. For example, the average entry diameter 512 may be less than 200 microns, or even less than 100 microns. The average entry diameter 512 may be larger than the average exit diameter 510. In an embodiment, both the average exit and entry diameters 510, 512 are less than 100 microns, and may be less than 80 microns. The perforations 280 shown in FIG. 13 are depicted larger than reality, relative to the section 502, for ease of description.

The laser device 500 is controlled to direct the laser beam 504 at different locations within a perforation zone 514 along the interior surface 264 of the lipskin 236. The perforation zone 514 may align with the leading edge section 258 shown in FIG. 5 . The perforation zone 514 encompasses the leading edge 210 of the lipskin 236. The total area of the perforations 280 along the interior surface 264 of the CFRP composite panel 270 may be expressed as a percent open area. The percent open area may represent the combined area of the perforations 280 as a percentage of the area of the perforation zone 514. In an embodiment, the percent open area of the perforation zone 514 is less than 2%, and may be less than 1%. The low percent open area is attributable to the micron-sized perforations 280 and relatively large pitch or spacing between the perforations 280. For example, the pitch between perforations 280 may be between mm and 1.5 mm. The density of the perforations 280 may be about 50 to about 400 perforations per square inch, such as about 200 perforations per square inch. The diameters, spacing, and density of perforations 280 may be selected based on application-specific parameters. Optionally, the diameters, spacing, and/or density of the perforations 280 may vary along different portions of the perforation zone 514.

The laser device 500 may be any laser device that is capable of providing the micron scale perforations described above while inflicting minimal damage to the surrounding fibers and matrix of the CFRP material. As shown in FIG. 13 , the single laser device 500 drills each perforation 280 through the entire thickness of the lipskin 236 from a single position. For example, the laser device 500 does not ablate a first portion of each perforation 280 from the inside position shown in FIG. 13 and then ablate a second portion of each perforation 280 from an outside position facing the exterior surface 248. Furthermore, multiple lasers are not used to drill each perforation 280. In an embodiment, the laser device 500 is a fiber laser that has a green frequency range. For example, the wavelength of the beam 504 may be about 532 nm.

The optics and parameters of the laser device 500 may be focused so that the hole dimensions are narrow and penetrate through the length of the material stack of the lipskin 236 to minimize the area of damage through the material stack. The optics and parameters may be adjusted to mitigate heat damage to the surrounding surface material and to prohibit CFRP material of the composite panel 270 from being exposed to the environment through the metallic coating 272, which would degrade the CFRP material. During the laser drilling process, the laser device 500 may be controlled to emit multiple pulses of electromagnetic energy with a designated amount of time between pulses to allow for cooling of the material surrounding the perforation 280. For example, the laser pulses impinge upon the lipskin 236 and gradually ablate material from the lipskin 236 (e.g., first the CFRP material then the metallic material) to define the perforation 280. The intervals between the pulses allow for heat dissipation, such that the thermal energy that conducts into the areas surrounding the perforations 280 is limited and does not damage the material.

In an embodiment, the section 502 of the lipskin 236 is formed to have a curved contour, as shown in FIG. 13 , prior to receiving the laser drilling. The laser beams impinge upon a curved interior surface 264. Although only a section 502 of the lipskin 236 is shown in FIG. 13 , in an embodiment the lipskin 236 is assembled into the annular barrel shape shown in FIGS. 3 and 4 prior to the laser drilling process, and the laser device 500 emits beams into the assembled annular barrel-shaped lipskin 236. In an alternative embodiment, the laser drilling may be performed on discrete sections of the lipskin 236 prior to coupling the sections together to define the annular barrel shape. For example, the sections may be four contoured quadrants that are individually laser drilled to define perforations 280 in each quadrant, and then the quadrants are coupled together to assembly the annular barrel.

FIG. 14 illustrates a perforation forming system 600 according to an embodiment. The perforation forming system 600 may be used to laser drill the perforations 280 (shown in FIGS. 6 and 13 ) into the lipskin 236. The system 600 may include the laser device 500, the lipskin 236, and a control unit 602 that includes one or more processors. The control unit 602 is operably connected to the laser device 500 via a wired or wireless communication pathway to control operation of the laser device 500 based on programmed instructions. The control unit 602 controls the laser device 500 to laser drill the plurality of perforations 280 through the lipskin 236. The system 600 may be set up for the laser device 500 to emit a laser beam 504 that impinges upon the interior surface 264 of the lipskin 236 and penetrates the CFRP material of the composite panel 270 before penetrating the metallic coating 272 and exiting the lipskin 236 through the exterior surface 248.

As shown in FIG. 14 , the lipskin 236 has an annular barrel shape. Optionally, the acoustic panel 238 is not yet assembled to the lipskin 236 to form the inlet cowl 206 (shown in FIG. 4 ) at the laser drilling stage, which provides more space for the laser device 500 to operate. In an embodiment, the system 600 also includes a positioning platform 604 on which the lipskin 236 is mounted. The positioning platform 604 may include one or more rollers 606 that engage and support the lipskin 236. Optionally, one or more of the rollers 606 may be powered to rotate the lipskin 236. The control unit 602 optionally may be mounted within the positioning platform 604. In an alternative embodiment, the control unit 602 may be mounted within the laser device 500 or another component of the system 600 other than the positioning platform 604.

The laser device 500 may be disposed within the central opening 230 of the annular barrel shaped lipskin 236. The laser device 500 may be held by an effector arm 608 of the system 600. The effector arm 608 may be stationary, or alternatively may include one or more actuators for controlled movement of the laser device 500 relative to the lipskin 236. The laser device 500 may have a scanning head that is controlled by the control unit 602 to aim the laser beam 504 at multiple locations over time without reorienting the laser device 500. The scanning head may be a galvo scan head.

In an embodiment, the system 600 includes a surface detector sensor 610 mounted to the laser device 500 and operably connected to the control unit 602. The surface detector sensor 610 may generate sensor data indicative of a distance from a beam-emitting lens 612 of the laser device 500 to the interior surface 264 of the lipskin 236. The sensor 610 may be a proximity sensor, a range finder, and/or the like. The control unit 602 may receive the sensor data and analyze the sensor data to control one or more parameters of the laser device 500 based on the sensor data. For example, in response to determining that the distance has changed, the control unit 602 may modify the position of the laser device 500 relative to the lipskin 500 and/or optics of the laser 500 to adjust the focal point of the laser beam 504 accordingly.

The system 600 may include a fume extractor device 614 configured to extract gaseous byproducts from the air that are produced by the laser drilling of the lipskin 236. The fume extractor device 614 may filter the air. Optionally, the fume extractor device 614 may be a wet scrubber. The gaseous byproducts may be generated by the laser ablation of the CFRP material. The control unit 602 may control the fume extractor device 614 to operate concurrently with the laser drilling of the lipskin 236 to remove the gaseous byproducts from the air while the byproducts are generated.

FIG. 15 is a flow chart 700 of a method for producing a perforated inlet assembly of a nacelle according to an embodiment. The method may include additional steps, fewer steps, and/or different steps than the steps illustrated in the flow chart 700. At step 702, a composite panel 270 is formed that includes a carbon fiber reinforced polymer (CFRP) material. The composite panel 270 may be formed to have a curved contour that represents at least a portion of an annular barrel shape. For example, the panel 270 may define an entirety of the annular barrel shape, or a sub-portion such as a quadrant of the annular barrel shape.

At step 704, a metallic coating 272 is applied to the composite panel 270 to form a lipskin 236. The metallic coating 272 may be applied such that the metallic coating 272 defines an exterior surface 248 of the lipskin 236 and the composite panel 270 defines an interior surface 264 of the lipskin 236. The metallic coating 272 may be a nickel alloy, such as a NiCo alloy. The metallic coating 272 may be applied via electroplating.

In an embodiment in which the lipskin 236 is in sections, the method may include coupling the sections of the lipskin 236 together to assemble the annular barrel shape after applying the metallic coating 272. Alternatively, the annular barrel shape of the lipskin 236 may be assembled prior to the application of the metallic coating 272.

At step 706, a plurality of perforations 280 are laser drilled through the lipskin 236. The laser drilling may include controlling a laser device 500 to emit a laser beam 504 that impinges upon the interior surface 264 of the lipskin 236 and penetrates the CFRP material of the composite panel 270 before penetrating the metallic coating 272 and exiting the lipskin 236 through the exterior surface 248. Optionally, during the laser drilling step, a fume extractor device 614 may be operated to extract gaseous byproducts from the air that are produced by the laser drilling of the lipskin 236. The laser drilling may be controlled by the control unit 602 to provide micron scale hole diameters as described herein.

At step 708, an inlet cowl 206 is assembled by coupling an acoustic panel 238 to the lipskin 236 after the laser drilling of the perforations 280. The acoustic panel 238 is disposed along an inner side of the inlet cowl 206. At step 710, an inlet assembly 240 is assembled by mounting a plenum back wall 260 to the interior surface 264 of the lipskin 236 to define a plenum 267 that is fluidly connected to the perforations 280. The plenum back wall 260 is a component of the FIPS 262 that supplies an anti-ice liquid into the plenum 267 for the anti-ice liquid in the plenum 267 to penetrate through the perforations 280 onto an exterior surface 248 of the inlet cowl 206 along a leading edge section 258 of the inlet cowl 206. The assembly of the inlet assembly 240 may include installing one or more support frames 250 within a cavity 242 of the inlet cowl 206 to structurally support the contour and shape of the inlet cowl 206.

Further, the disclosure comprises examples according to the following clauses:

Clause 1. A method for producing a nacelle inlet assembly, the method comprising:

-   -   forming a composite panel that includes a carbon fiber         reinforced polymer (CFRP) material, the composite panel formed         to have a curved contour that represents at least a portion of         an annular barrel shape;     -   applying a metallic coating to the composite panel to form a         lipskin, the metallic coating applied such that the metallic         coating defines an exterior surface of the lipskin and the         composite panel defines an interior surface of the lipskin; and         laser drilling a plurality of perforations through the lipskin,         wherein the laser drilling comprises emitting a laser beam that         impinges upon the interior surface of the lipskin and penetrates         the CFRP material of the composite panel before penetrating the         metallic coating and exiting the lipskin through the exterior         surface.

Clause 2. The method of Clause 1, wherein the perforations are laser drilled through the lipskin at different locations within a perforation zone of the lipskin that encompasses a leading edge of the lipskin, and a percent open area of the perforation zone is less than 2%.

Clause 3. The method of Clause 1 or Clause 2, wherein the perforations are laser drilled through the lipskin to have an average exit diameter at the exterior surface of less than 100 microns.

Clause 4. The method of Clause 3, wherein the average exit diameter at the exterior surface of is less than 60 microns.

Clause 5. The method of any of Clauses 1-4, wherein the perforations are laser drilled through the lipskin to have an average entry diameter at the interior surface of less than 400 microns.

Clause 6. The method of Clause 5, wherein the average entry diameter at the interior surface is less than 100 microns.

Clause 7. The method of any of Clauses 1-6, wherein forming the composite panel comprises laying up multiple plies of CFRP material in a stack on a mandrel and curing the stack.

Clause 8. The method of any of Clauses 1-7, wherein the metallic coating is applied via electroplating.

Clause 9. The method of any of Clauses 1-8, wherein the metallic coating comprises a nickel cobalt (NiCo) alloy.

Clause 10. The method of any of Clauses 1-9, further comprising operating a fume extractor device concurrent with the laser drilling, the fume extractor device configured to extract gaseous byproducts from the air that are produced by the laser drilling of the lipskin.

Clause 11. The method of any of Clauses 1-10, wherein the lipskin is one section of the annular barrel shape, and the method comprises assembling multiple sections of the lipskin together to complete the annular barrel shape prior to laser drilling the perforations through the lipskin.

Clause 12. The method of any of Clauses 1-11, further comprising assembling an inlet cowl by coupling an acoustic panel to the lipskin after the laser drilling.

Clause 13. The method of Clause 12, further comprising assembling an inlet assembly by installing one or more support frames within a cavity defined between an inner side of the inlet cowl and an outer side of the inlet cowl.

Clause 14. The method of Clause 12 or Clause 13, further comprising assembling an inlet assembly by coupling a plenum back wall along the interior surface of the lipskin to define a plenum that is fluidly connected to the perforations.

Clause 15. The method of any of Clauses 1-14, wherein the perforations are laser drilled to have between 0.5 mm and 1.5 mm pitch between the perforations.

Clause 16. The method of any of Clauses 1-15, wherein the perforations are laser drilled by a single fiber laser device, and laser beam emitted by the fiber laser device has a wavelength of about 532 nm.

Clause 17. A perforation forming system comprising:

-   -   a laser device;     -   a lipskin having a curved contour and including an interior         surface and an exterior surface, the lipskin including a         metallic coating that defines the exterior surface and a         composite panel that defines the interior surface, the composite         panel including a carbon fiber reinforced polymer (CFRP)         material; and     -   a control unit operably connected to the laser device and         configured to control the laser device to laser drill a         plurality of perforations through the lipskin, wherein each of         the perforations is formed by the laser device emitting a laser         beam that impinges upon the interior surface of the lipskin and         penetrates the CFRP material of the composite panel before         penetrating the metallic coating and exiting the lipskin through         the exterior surface.

Clause 18. The perforation forming system of Clause 17, further comprising a fume extractor device configured to extract gaseous byproducts from the air that are produced by the laser drilling of the lipskin.

Clause 19. The perforation forming system of Clause 17 or Clause 18, further comprising a surface detector sensor mounted to the laser device and operably connected to the control unit, the surface detector sensor configured to generate sensor data indicative of a distance from a beam-emitting lens of the laser device to the interior surface of the lipskin, and the control unit is configured to control one or more parameters of the laser device based on the sensor data.

Clause 20. A method for producing a nacelle inlet assembly, the method comprising:

-   -   forming a composite panel that includes a carbon fiber         reinforced polymer (CFRP) material, the composite panel formed         to have a curved contour that represents at least a portion of         an annular barrel shape;     -   applying a metallic coating to the composite panel to form a         lipskin, the metallic coating including a nickel cobalt (NiCo)         alloy, the metallic coating defining an exterior surface of the         lipskin and the composite panel defining an interior surface of         the lipskin; and     -   laser drilling a plurality of perforations through the lipskin,         wherein the laser drilling comprises emitting a laser beam that         impinges upon the interior surface of the lipskin and penetrates         the CFRP material of the composite panel before penetrating the         metallic coating and exiting the lipskin through the exterior         surface,     -   wherein the perforations are laser drilled through the lipskin         to have an average entry diameter at the interior surface of         less than 100 microns and an average exit diameter at the         exterior surface of less than 60 microns.

While various spatial and directional terms, such as top, bottom, lower, mid, lateral, horizontal, vertical, front and the like may be used to describe embodiments of the present disclosure, it is understood that such terms are merely used with respect to the orientations shown in the drawings. The orientations may be inverted, rotated, or otherwise changed, such that an upper portion is a lower portion, and vice versa, horizontal becomes vertical, and the like.

As used herein, a structure, limitation, or element that is “configured to” perform a task or operation is particularly structurally formed, constructed, or adapted in a manner corresponding to the task or operation. For purposes of clarity and the avoidance of doubt, an object that is merely capable of being modified to perform the task or operation is not “configured to” perform the task or operation as used herein.

Diagrams of embodiments herein may illustrate one or more control or processing units, such as the control unit 602 shown in FIG. 14 . It is to be understood that the processing or control units may represent circuits, circuitry, or portions thereof that may be implemented as hardware with associated instructions (e.g., software stored on a tangible and non-transitory computer readable storage medium, such as a computer hard drive, ROM, RAM, or the like) that perform the operations described herein. The hardware may include state machine circuitry hardwired to perform the functions described herein. Optionally, the hardware may include electronic circuits that include and/or are connected to one or more logic-based devices, such as microprocessors, processors, controllers, or the like. Optionally, the control unit 602 may represent processing circuitry such as one or more of a field programmable gate array (FPGA), application specific integrated circuit (ASIC), microprocessor(s), a quantum computing device, and/or the like. The circuits in various embodiments may be configured to execute one or more algorithms to perform functions described herein. The one or more algorithms may include aspects of embodiments disclosed herein, whether or not expressly identified in a flowchart or a method.

As used herein, the term “control unit,” “unit,” “central processing unit,” “CPU,” “computer,” or the like may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor including hardware, software, or a combination thereof capable of executing the functions described herein. Such are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of such terms. The control unit 602 shown in FIG. 14 is configured to execute a set of instructions that are stored in one or more storage elements (such as one or more memories), in order to process data. For example, the control unit 602 may include or be coupled to one or more memories. The storage elements may also store data or other information as desired or needed. The storage elements may be in the form of an information source or a physical memory element within a processing machine.

The set of instructions may include various commands that instruct the control unit 602 as a processing machine to perform specific operations such as the methods and processes of the various embodiments of the subject matter described herein. The set of instructions may be in the form of a software program. The software may be in various forms such as system software or application software. Further, the software may be in the form of a collection of separate programs, a program subset within a larger program or a portion of a program. The software may also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.

As used herein, the terms “software” and “firmware” are interchangeable, and include any computer program stored in memory for execution by a computer, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. The above memory types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the disclosure, the embodiments are by no means limiting and are example embodiments. Many other embodiments will be apparent to those of ordinary skill in the art upon reviewing the above description. The scope of the various embodiments of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.

This written description uses examples to disclose the various embodiments of the disclosure, including the best mode, and also to enable any person skilled in the art to practice the various embodiments of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the various embodiments of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if the examples have structural elements that do not differ from the literal language of the claims, or if the examples include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. A method for producing a nacelle inlet assembly, the method comprising: forming a composite panel that includes a carbon fiber reinforced polymer (CFRP) material, the composite panel formed to have a curved contour that represents at least a portion of an annular barrel shape; applying a metallic coating to the composite panel to form a lipskin, the metallic coating applied such that the metallic coating defines an exterior surface of the lipskin and the composite panel defines an interior surface of the lipskin; and laser drilling a plurality of perforations through the lipskin, wherein the laser drilling comprises emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface.
 2. The method of claim 1, wherein the perforations are laser drilled through the lipskin at different locations within a perforation zone of the lipskin that encompasses a leading edge of the lipskin, and a percent open area of the perforation zone is less than 2%.
 3. The method of claim 1, wherein the perforations are laser drilled through the lipskin to have an average exit diameter at the exterior surface of less than 100 microns.
 4. The method of claim 3, wherein the average exit diameter at the exterior surface of is less than 60 microns.
 5. The method of claim 1, wherein the perforations are laser drilled through the lipskin to have an average entry diameter at the interior surface of less than 400 microns.
 6. The method of claim 5, wherein the average entry diameter at the interior surface is less than 100 microns.
 7. The method of claim 1, wherein forming the composite panel comprises laying up multiple plies of CFRP material in a stack on a mandrel and curing the stack.
 8. The method of claim 1, wherein the metallic coating is applied via electroplating.
 9. The method of claim 1, wherein the metallic coating comprises a nickel cobalt (NiCo) alloy.
 10. The method of claim 1, further comprising operating a fume extractor device concurrent with the laser drilling, the fume extractor device configured to extract gaseous byproducts from the air that are produced by the laser drilling of the lipskin.
 11. The method of claim 1, wherein the lipskin is one section of the annular barrel shape, and the method comprises assembling multiple sections of the lipskin together to complete the annular barrel shape prior to laser drilling the perforations through the lipskin.
 12. The method of claim 1, further comprising assembling an inlet cowl by coupling an acoustic panel to the lipskin after the laser drilling.
 13. The method of claim 12, further comprising assembling an inlet assembly by installing one or more support frames within a cavity defined between an inner side of the inlet cowl and an outer side of the inlet cowl.
 14. The method of claim 12, further comprising assembling an inlet assembly by coupling a plenum back wall along the interior surface of the lipskin to define a plenum that is fluidly connected to the perforations.
 15. The method of claim 1, wherein the perforations are laser drilled to have between 0.5 mm and 1.5 mm pitch between the perforations.
 16. The method of claim 1, wherein the perforations are laser drilled by a single fiber laser device, and laser beam emitted by the fiber laser device has a wavelength of about 532 nm.
 17. A perforation forming system comprising: a laser device; a lipskin having a curved contour and including an interior surface and an exterior surface, the lipskin including a metallic coating that defines the exterior surface and a composite panel that defines the interior surface, the composite panel including a carbon fiber reinforced polymer (CFRP) material; and a control unit operably connected to the laser device and configured to control the laser device to laser drill a plurality of perforations through the lipskin, wherein each of the perforations is formed by the laser device emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface.
 18. The perforation forming system of claim 17, further comprising a fume extractor device configured to extract gaseous byproducts from the air that are produced by the laser drilling of the lipskin.
 19. The perforation forming system of claim 17, further comprising a surface detector sensor mounted to the laser device and operably connected to the control unit, the surface detector sensor configured to generate sensor data indicative of a distance from a beam-emitting lens of the laser device to the interior surface of the lipskin, and the control unit is configured to control one or more parameters of the laser device based on the sensor data.
 20. A method for producing a nacelle inlet assembly, the method comprising: forming a composite panel that includes a carbon fiber reinforced polymer (CFRP) material, the composite panel formed to have a curved contour that represents at least a portion of an annular barrel shape; applying a metallic coating to the composite panel to form a lipskin, the metallic coating including a nickel cobalt (NiCo) alloy, the metallic coating defining an exterior surface of the lipskin and the composite panel defining an interior surface of the lipskin; and laser drilling a plurality of perforations through the lipskin, wherein the laser drilling comprises emitting a laser beam that impinges upon the interior surface of the lipskin and penetrates the CFRP material of the composite panel before penetrating the metallic coating and exiting the lipskin through the exterior surface, wherein the perforations are laser drilled through the lipskin to have an average entry diameter at the interior surface of less than 100 microns and an average exit diameter at the exterior surface of less than 60 microns. 